A lithography process in which a resist underlayer film is provided between a substrate and a resist film formed on the substrate, and a resist pattern of desired shape is formed has been known. However, a conventional resist underlayer film, for example, a resist underlayer film formed from a composition containing an aminoplast crosslinker, described in Patent Document 1, has poor resistance to a basic aqueous hydrogen peroxide solution. Therefore, such a resist underlayer film cannot be used as a mask in an etching process using the basic aqueous hydrogen peroxide solution.
Patent Document 2 describes an underlayer film-forming composition for lithography containing a compound having a protected carboxyl group, a compound having a group capable of reacting with a carboxyl group, and a solvent, or an underlayer film-forming composition for lithography containing a compound having a group capable of reacting with a carboxyl group and a protected carboxyl group and a solvent. The compositions do not contain an aminoplast crosslinker as an essential component. However, Patent Document 2 does not describe or suggest resistance of resist underlayer films formed from the compositions to the basic aqueous hydrogen peroxide solution.